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Tuesday, 30 September 2014

To the Deputy of the People's Commissar of Medium Machinebuilding, comrade A.A. Goreglyad
Copy to the Chief of the NKSM Glavspetsmash, comrade Surenyan

On the issue of the heavily armoured IS tank.

I propose this heavy IS tank project, composed according to the orders of the NKSM.

Our factory agrees to produce the project, working blueprints, and experimental prototype, and considers it possible to produce up to 30 vehicles annually using the capabilities of the experimental division (formerly factory #185). In order to ensure such volume, cooperation among a series of factories is necessary, both from our Commissariat and others which supply our factory with raw materials and components. Additionally, the factory will need more equipment. An approximate calculation of required equipment and cooperation plans are included in the attachment.

Reply with your decision.

Attachment: explanatory note to the NKSM (two copies), to Glavspetsmash (one copy) and for the archive.
Preliminary cooperation plan for the NKSM (two copies), for Glavspetsmash (one copy) and for the archive.

The project completed by Voroshilov factory #174 fills the need of a breakthrough tank in a positional war.

The main tasks of this tank are the destruction of long-term reinforced concrete artillery emplacements, artillery, and heavy enemy tanks. These tanks can also serve as a powerful coastal defense gun, aiding in deflecting enemy landing attempts. The armour (main thickness: 110 mm) is thick enough to withstand all artillery installed in concrete emplacements, from 37 mm to 88 mm inclusive.

For instance, Germany uses an 88 mm AA gun with the muzzle velocity of 820 m/s. It is possible that this gun can be put in a bunker. It is unlikely that larger caliber guns will be placed in bunkers due to low rates of fire and difficulty in hitting moving targets up close. Additionally, high caliber artillery has no armour piercing shells, and its long barrels will reveal its location.

The tank is armed with a powerful 130 mm B-13 gun with a muzzle velocity of 880 m/s, using a 36 kg shell. Due to its powerful penetration (the gun can penetrate 150 mm of armour from a kilometer away), a shot that hits a bunker or pillbox will destroy it.

When firing a concrete piercing shell, up to two meters of concrete can be breached, with a fragmentation power approaching that of the 152 mm ML-20 shell.

The turret can spin in a full circle, and has a 2400 mm turret ring.

The presence of a semi-automatic breech, loading tray, gun rammer, and bore evacuator increase the rate of fire and make the crew's working conditions better. The hull can be made of rolled or cast armour. The tank has four machineguns for protecting itself from enemy infantry. Two of these are in turrets, which can quickly shift fire between land and airborne threats. One of these turrets solves the issue of granting the commander 360 degree vision. It's possible to use the turret for observation only, but then the advantage of rapidly shifting fire is lost. The tank can carry 50 shells for its main armament, which allows it to operate on the battlefield for a long span of time.

Instead of a B-13 gun, a 122 mm A-19 corps gun can be installed, with a muzzle velocity of 820 m/s and a 25 kg shell, or a 152 mm ML-20 corps gun with a muzzle velocity of 650 m/s and a 44.5 kg shell. The rate of fire of the 122 mm gun is close to that of the 130 mm gun and is significantly higher than of the 152 mm gun.

The vehicle uses the 24-cylinder V-24 engine, 1100-1200 hp, composed of a pair of V-2 engines in one unit. This engine uses parts produced by factory #75, and an experimental prototype can be built in 4-5 months.

Aside from the above engine, the tank can use the 12-cylinder MN-1 1000 hp engine, a batch of which was already produced by Ts.I.A.M. or a turbocharged V-2 engine at 850 hp, with a lower top speed.

The engine can grant the vehicle a speed of up to 35 kph, and the ability to traverse light obstacles and very rough terrain. As for off-road performance, it is difficult to achieve in this class of vehicle, as the ground pressure is limited by the size of railroads, maximum possible width, and internal volume.

With 800 mm wide tracks and 110 mm thick armour, given zeroth volume category (width: 3400 mm), the internal width of the hull ends up being 1560 mm, which is less than that of the light T-26 tank, where it is 1625 mm. This project has the ground pressure of 0.9 kg/cm^2.

In order to reduce the ground pressure on soft terrain, it is possible to replace the 800 mm wide tracks with 1 meter wide tracks, at which point ground pressure decreases to 0.75 kg/cm^2. The narrower tracks can be equipped for railroad transport and use on solid ground or in winter conditions. The size of the vehicle fits within the zeroth category. According to NKPS instructions (TransZhelDorIzdat, 1938), a load of these dimensions can be transported without restrictions on Soviet railroads.

The combat mass of the tank is 75 tons. Considering that the mass of the vehicle without ammunition, equipment, fuel, and crew is no more than 70 tons, they can be transported on 60 ton train cars with acceptable overloads. If the turret and hull are transported separately, existing platforms (even 50 ton ones) fully enable the transport of this tank.

The transmission and engine group is in the rear of the tank. The cooling fan is on the axis of the crankshaft, and is the two-stage axle type. The air is sucked in at the top of the vehicle, and exhausted on the bottom, near the tracks. The transmission is mechanical, with five speeds forward and one back.

In order to make the transmission as small as possible, the friction clutches are inverted and placed behind the final drives above the suspension, in a box that is the continuation of the turret platform. The turret is in the middle of the vehicle. The ammunition is placed in the perimeter of the turret, in the hull, and in the turret bustle.

Fuel tanks are located in the fighting compartment, and act as a floor for the gun crew. The engine and transmission can be accessed through special hatches and passages.

As it is difficult to protect the suspension from artillery fire, there is a divide between the protection of the hull and suspension.

Variant 2. This variant has significant differences in its design (blueprints IS-S-1, IS-S2-1, IS-S3-1, IS-S4-1). In order to protect the suspension, a separate track is used. Each side has two independent tracks, each of which is driven independently. To achieve this, the transmission and engine group is in the middle of the vehicle, and each side has two drive wheels. If one track per side is destroyed, the tank can still continue on its course. In addition, the front idler can be modified to be used as a mine roller. If the front track is hit and falls off, it protects the rear track from being damaged by explosives. In order to obtain a sufficiently large surface, the tank's hull is increased in length by 600 mm. That and the increase in weight due to the suspension results in a tank weight of 79 tons. In order to achieve the desired weight of 75 tons, the main armour thickness must either be reduced to 100 mm or the turret must be transported separately.

Due to a reduction in track surface area, the ground pressure increases to 1.05 kg/cm^2 without sinking and 0.85 kg/cm^2 when sunken by 100 mm.

The crew is separated, and can exit trough two emergency hatches underneath the tank.

Characteristic

Two-track Variant

Four-track Variant

Mass (tons)

75

79

Size (mm)

Length of tracks

7400

8020

Width

3400

3400

Height (to roof)

3150

3158

Height (to highest point)

3500

3500

Clearance

540

540

Length of the track's gripping surface

5250

4440

Track width

800

800

Distance between track centers

2600

2600

Armour (mm)

Sides, turret platform, front and rear, turret side

110

100

Floor

40

40

Roof

40

40

Armament

Main gun

130 mm B-13

Muzzle velocity (m/s)

880

Shell mass (kg)

36

Horizontal traverse range (deg.)

360

Gun elevation (deg.)

+12

Gun depression (deg.)

-5

Turret ring diameter (mm)

2400

Optional armament

45 mm gun

Machineguns

4

Machinegun bullets

5000

Gun shells

50

58

Mobility

Engine power (hp)

1100-1200

Speed, kph

5th gear

32.3

4th gear

20.4

3rd gear

13.5

2nd gear

9.2

1st gear

4.8

Reverse gear

5.6

Traversible obstacles

Trench width (meters)

3.5

3.7

Grade (deg.)

40-42

Water depth (meters)

1.6

Ground pressure (kg/cm^2)

0.9

1.05

L/B ratio

2.02

2.24

Crew

6

The cost of the vehicle when produced in small batches is no more than 3 million rubles, which compares favourably to the cost of the 100-Y vehicle (the cost of one is 3.3 million rubles).

If the project is approved immediately, the first prototype will be ready by June-July of 1941, and the first batch will be ready in the first quarter of 1942.

Monday, 29 September 2014

The Battle of Kursk was still raging on when the Red Army delivered a new strike against the Germans, this time at Smolensk. The region where the Suvorov Strategic Offensive Operation was to take place was called "the Gate of Smolensk", as it is the shortest path from the West to Moscow. The West and Kalinin Fronts were tasked with penetrating the deep German defensive line, defeating the left flank of Army Group Center, and slamming the gates shut.

The operation lasted 57 days, from August 7th to October 2nd 1943. The Soviet forces, numbering 1.2 million men, 1436 tanks and about 20600 guns were opposed by German forces, numbering 850,000 men, 500 tanks and SPGs, and about 8800 guns and mortars. The Germans held deep echeloned defensive lines, breaking through which would not be easy.

Travelling Light

The tank units that participated in the Smolensk operation were formed from what was available. As a result, it turned out that the majority of the units were composed of obsolete and foreign vehicles: Matildas, Valentines, Stuarts. They were poorly armoured and weakly armed. For instance, in the 5th Mechanized Corps, 182 tanks out of 193 were British or American. In the 42nd Guards Tank Brigade, 22 tanks out of 51 were light T-60 and T-70 tanks.

The Soviet staff knew that the operation would be a long one, lasting at least a month. However, tanks only had 3-4 loads of ammunition and fuel. For a prolonged offensive, this is not enough. However, the Red Army fought through all of August in these difficult conditions. Despite the shortages, the Soviet forces reached the German positions around Smolensk.

In early September, the Red Army forces stopped to regroup. HQ finally managed to gather up reinforcements. The offensive resumed on September 15th. The Red Army penetrated the enemy lines in nearly all directions. When tanks and infantry would reach the first trenches, artillery would begin bombarding the second line. On September 16th, Yartsevo was liberated, on the 21st, Demidov. On September 25th, the Red Army displaced the Germans from Smolensk and Roslavl.

Despite all difficulties, tanks were able to provide help for infantry and artillery throughout the operation. The region was covered in rivers and swamps, and tank units were forced to serve as infantry support in a complete absence of roads. There were cases when heavy KV tanks would render a bridge or a road unusable after driving over it, making it necessary to discover new paths.

A story of one hero

Tens of thousands of soldiers earned orders and medals as a result of this operation. Among those that earned the title of Hero of the Soviet Union was the commander of the 242nd Tank Battalion of the 28th Guards Tank Brigade, Captain Georgiy Andreevich Ponomarev.

He passed his trial by fire in the fall of 1941 at Volokolamsk, as a BT-7 platoon commander. When fighting under Rzhev, Ponomarev's brigade excelled in battle, and earned the Guards title.

From September 14th, Captain Ponomarev participated in the breakthrough at Smolensk. In the outskirts of Rudna, his T-34 destroyed 7 anti-tank guns, one 150 mm gun, 5 trucks with infantry and cargo, 4 mortar batteries, and over 200 soldiers and officers of the enemy.

At Rudna, the Germans attempted to counterattack, but Soviet tanks deflected the attempt, and threw them back to initial positions. An artillery battery impeded further Soviet progress. Guards Captain Ponomarev destroyed two of its guns with return fire and crushed a third under his tracks, but a shell managed to penetrate his T-34. A fire started, but the crew kept fighting. The burning T-34 burst into the city. Hours later, the city was liberated. The heavily wounded Ponomarev was taken to the nearest hospital at Demidov, but he died on the way.

By October 2nd, forces of the West and Kalinin Fronts reached a line west of Velizh, Rudna and Proni river. Under orders from Supreme Command, they fortified for a defense. The Smolensk Strategic Offensive Operation was completed.

Article author: Nikolai Nevskiy.

Nikolai Nevskiy is a historian, specializing in Soviet tank production in the Great Patriotic War.

Sunday, 28 September 2014

"To the deputy chief of the GAU KA and the chair of the Artkom, Major-General of Artillery, comrade Hohlov

On the issue of: 57 mm Charnko-Komaritskiy AT gun

According to the orders of the Technical Department of the NKV and the wishes of the GAU KA chief, Colonel-General Yakovlev and the MK and MGK VKP(b) secretary comrade Sherbakov stated when demonstrating the 37 mm AT gun at OKB-46, the latter designed a 57 mm anti-tank gun based on the Charnko-Komaritskiy principle with the following characteristics.

Caliber: 57 mm

Shell mass: 3.14 kg

Muzzle velocity: 950 m/s

Bore axis height: 550 mm

Horizontal range: 360 degrees

Vertical range: from +20 to -5 degrees

Mass: 550 kg

Rate of fire: 20 RPM

Breech: sliding, semi-automatic

Mount: sprung, maximum movement speed 70 kph

The project is scheduled for completion on August 1st of this year. I ask you to notify the Technical Council of the NKV of Artkom's data on the 57 mm Charnko-Komaritskiy AT gun.

Saturday, 27 September 2014

"Tank: Death Sower, for creation of passages in minefields and creating shrapnel cloud

Making passages in minefields is difficult and dangerous work, consuming large amounts of time and causing many losses. Frequently, it is not possible to make passages in advance, and they have to be made during the offensive, which inevitably delays the operation and results in missed deadlines.

Of many methods of minefield clearing, the method of using explosive charges found widespread use. According to experience (Military Engineering magazine issue #3 for 1942, page 45, Military Engineer 1st Grade Morin's article), passages up to 8 meters wide can be cleared using properly selected charges.

The proposed device mechanizes the above procedures and allows the tank to clear passages in minefields without losing speed during an offensive.

The same device allows for the creation of a shrapnel cloud in front of the tank, striking all targets in an area 50-100 meters wide. This mode of operation is useful when pursuing the enemy.

The device consists of a magazine (1) made from 10-20 mm thick steel (for protection from bullets and shrapnel), loaded with F-1 hand grenades equipped with a special detonator or custom made charges up to 3 kilograms in weight.

The firing mechanism consists of a round or rectangular barrel (2) with a plunger (3). The spring (4) pushes against the end of the tube (5), which is adjustable to control the power of the spring. The spring is retracted automatically using a roller chain (6). The chain has an edge (7), and is moved using the transmission gears (8, 9), and the crankshaft (10) from the tank's engine or drive wheel.

When the chain moves, the edge (7) grabs on the rim (11) of the plunger (3) and pulls it back, compressing the spring (4), until the plunger clears the magazine, which will cause a grenade to fall into the barrel (1).

Upon further motion, the edge (7) slips off the rim (11) and the plunger (3) moves forward to throw the grenade out of the barrel to a distance of 5-20 meters, set by adjusting the end of the barrel (5).

The grenades or charges must detonate 0.5 meters before hitting the ground (the optimal height to clear mines) or when they hit the ground. Many detonators can be proposed. For instance, the F-1 grenade can be equipped with a #8 capsule detonator, put on a screwed-in cap with an opening that is filled with a powder charge. The time of burning can be set so the grenade explodes 0.5 meters above the ground. A grenade modified this way can be found on sketch #2.

The ignition of the powder can be achieved by sprinkling the grenade in KS fluid from a reservoir (12) when it leaves the barrel (2), where it is pressurized by inert gases (engine exhaust), fed in by two pipes (13) and equipped with an automatic valve (14), opened by the grenade when it flies out. This device is shown on sketch #1.

An explosive charge (several TNT charges tied together) can also be equipped with a similar detonator.

Other methods can be used to ignite the powder: friction igniters, burners, electrically heated coils, etc.

Mechanical methods of detonating the grenade, such as an inertial detonator (as with the RPG grenade), a lever detonator, drawn back when the grenade launches, or a contact detonator from mortar rounds.

The mechanism can also be modified to fire rounds from company or battalion mortars, which will not require any modifications and be effective both in destroying objects surrounding the tank and clearing minefields.

In cases of necessity, 2-3 mechanisms can be installed on one tank, clearing a wide area. The magazine is carried in front of the tank for safety, in case the explosives detonate after being hit by a shell, but it can be placed inside the tank to improve maneuverability.

The magazine should be equipped with a spinning loading gear, like on counting or wrapping devices, to make the loading process more reliable.

Friday, 26 September 2014

After taking apart the transmission and replacing broken components, trials continued. From October 26th to October 29th, the tank travelled 190 km. In total, the tank travelled 1160 km. Trials were paused for the following reasons:

The engine is hard to start. During the last trial stage (1070 km), the engine stopped starting, and only after replacing 3 nozzles in the left group did we manage to start the engine, with some difficulty.

The water radiator leaks (produced by the aircraft factory).

The 3rd gear transmission reductor friction clutch tore.

Vehicle #2:

Assembly and a 140 km trial run have been completed.

Maximum temperatures:

Water: 90 degrees

Oil in the engine: 90-92 degrees

Oil in the transmission: 95 degrees

Air temperature: 0 degrees

During trials, the oil radiator was replaced, as it was leaking (radiator produced by aircraft factory #34).

Vehicle #2 was being prepared for the state commission, and has the following improvements compared to vehicle #1:

Additional fuel tanks are connected to main fuel tanks, and have the appropriate valve on the driver's control panel.

A mechanism to jettison additional fuel tanks without leaving the tank has been added.

The radiator socket is removable.

The water and oil systems have been simplified.

A Panther type heater has been added for the water system.

A new type of air grille has been added with a reverse lock.

The transmission oil pump has been improved (40 L/min in 5th gear instead of 20)

Kimaf oil filter installed to clear the transmission oil.

The driver's pedals have been simplified and a ball bearing added to their axles.

Other small design improvements.

The hull of of the old type. The turret and gun are from vehicle #0, which has returned from trials at the Gorohovets proving grounds.

The factory has made the decision to perform 1000 km of mobility trials with vehicle #2.

Thursday, 25 September 2014

LTTB
The acronym has a rather oxymoronic meaning: Light Tank with Heavy Armour (Legkiy Tank Tyazhelogo Bronirovaniya). However, if one looks at the requirements sent by the military to the Omsk tank factory in 1944, everything falls in its place.

The LTTB was meant for recce in force. Because of this, it was supposed to have good armour protection from the front. The sides were about on the level of a T-34, up to 45 mm. The tank was first planned with a 76 mm gun, but it was later replaced with an 85 mm S-53.

In theory, this tank could be useful for the army. Fast, well protected, effectively armed. However, the production of the LTTB would have been too complicated. It would have to start from scratch, which means new assembly lines, extra spending, extensive trials. Neither the extra time nor money existed for this project, as the factory was busy producing T-34-85s. In the end, the design never left paper.

T-54 Lightened
The project was developed at factory #183 in Nizhniy Tagil, a producer of the regular T-54, in 1949. The vehicle was meant for special duties, for which the use of a regular T-54 was not possible.

The tank had thinner armour in the turret and hull, which allowed the reduction in mass from 36 tons to 31 tons. Additionally, the new vehicle would have had wider tracks, reducing ground pressure even further, and allowing for the vehicle to be used in difficult terrain.

Due to its lighter mass, the speed of the tank was expected to reach nearly 58 kph. The armament would have been the 100 mm D-10T. Work on the vehicle never made it past blueprints.

T37
This tank was designed as a replacement for the M24 Chaffee. The requirements for this vehicle were ready in early 1945. Work on the project started after the end of the war, when the American military budget was slashed.

The T37 received its designation in September of 1946. Initially, the military ordered three prototypes at the Detroit Arsenal, but this order was reduced to 2. The wooden mockup and technical documentation were ready by 1949. The vehicle was tested at Aberdeen in 1949-1950.

The T37 did not reach mass production. The Korean War, which began in 1950, forced some changes to the American design program. The T37 did not meet the new requirements, and a new vehicle was designed using it as a starting point, the T41.

M41 Walker Bulldog
The vehicle was initially indexed T41, and used many components of the T37. It was ready in 1948, and Cadillac Motors received an order for 100 vehicles, increased tenfold with the start of the Korean War, along with increased requirements for the engine, aiming mechanisms, and ammunition rack. In 1953, it was adopted into the Army under the index M41.

At first, the tank was to be called "little bulldog". However, after American General Walton Walker died in an airplane crash, the vehicle was renamed in his honour.

The Walker Bulldog was produced until the end of the 1950s, with over 3700 vehicles built. The tank was taken out of the American armed forces for its weak armour and armament, but continued service in some nations for many years.

T49
The Korean War and clashes of American vehicles with the T-34-85 forced the US military to consider greatly increasing the firepower of its vehicles, including light tanks.

In 1954, the T49 began trials at the Aberdeen Proving Grounds. The M41 chassis was equipped with a new turret and the 90 mm T231E3 gun. Trials of the T49 lasted until May of 1955, but the military demanded even greater firepower.

In the end, the T49 was equipped with a new 152 mm gun. T49 trials ended when a new chassis was developed, and the turret with the 152 mm gun was transferred over to it.

Spahpanzer Ru 251
This lesser known German experimental tank was based on the Kanonenjagdpanzer 4-5 vehicle with a 90 mm gun. Unusual, since usually SPGs are based on a tank chassis, and not the other way around.

The light, fast, and well armed Ru 251 was meant to replace the ageing Walker Bulldog in the German army. The Henschel company was tasked with production and testing. The tank was meant for reconnaissance battalions of tank divisions and other units. A notable feature of the vehicle was its speed, up to 80 kph. The Ru 251 had a 90 mm Rheinmetall gun.

Wednesday, 24 September 2014

Practice from previous years of preparation for parades on May 1st and November 7th shows that vehicles are sent in several days before a parade. The factory did not have time to carefully calibrate them, as a result there were cases of vehicles stalling while driving through Red Square. In the upcoming October parade, this cannot happen.

I order:

Personally hold factory directors responsible for supplying:

Voroshilov factory: 100 T-26 tanks, 25 armoured tractors.

Factory #37: 100 T-37 tanks.

Kharkov Locomotive Factory: 2 T-35s, one of which is the production type and the other is sent in for improvements from Leningrad.

OKMO experimental factory: one T-35 vehicle currently being modified.

All factories must immediately begin production and calibration such that vehicles will be ready by no later than October 1st and delivered to Moscow no later than October 10th.

Tuesday, 23 September 2014

In WWII, a pilot of a ground attack airplane or bomber flying at several hundred kph had a hard time placing a bomb next to a small target. And what if the target is moving, and what if it's well armoured?

In order to guarantee the destruction of an enemy medium tank with a FAB-100 bomb, the pilot needed to hit within 3 meters of the vehicle. This was difficult, and it was not surprising that the VVS was very interested in the special anti-tank bomb project proposed by I. A. Larionov.

This bomb, indexed PTAB 2.5-1.5 weighed 2.5 kg. The bomb used a HEAT type warhead, capable of penetrating 60 mm of armour 30 to 90 degrees. This was enough to destroy any German tank; even the well armoured Tiger only had 28 mm of armour on its hull and turret roof.

The Soviet Il-2 ground attacker could carry four cassettes, each of which carried 48 PTABs, or 220 individual bombs without cassettes. They were dropped simultaneously, covering a large area. The fact that most bombs would blow up ineffectively was meaningless, since one destroyed tank cost much more than the entire cassette of bombs put together.

The PTAB 2.5-1.5 was first used on July 5th, 1943, at Kursk, and proved themselves an effective weapon. Pilots of the 3rd and 9th corps of the 17th air army reported that 90 German tanks were destroyed with these new bombs by the end of July 6th. As the days went on, the effectiveness of the bombs was reduced, since the Germans started spacing out their vehicles. However, the PTAB was still more effective than conventional high explosive or fragmentation bombs.

The inventor of the bomb, I. A. Larionov, was rewarded with an Order of Lenin in 1944 and the Government Grant of the USSR in 1946.

"According to the resolution of the GAU KA chief, Colonel-General of Artillery, comrade Yakovlev, I report the conclusion of the GAU Artillery Committee on the 122 mm U-11 howitzer in the KV-9 tank.

The report given to the commission is not full. We have yet to establish the accuracy and expected deviations, recoil velocity curves (due to new recoil mechanisms, different from the stock 122 mm mod. 1938 howitzer), establishing the ballistics when firing AP shells, and testing penetration with stock shells.

The rate of fire, range, accuracy, ammunition capacity, and ease of use of the 122 mm howitzer are inferior to the 76 mm tank gun.As for the penetration of 110 mm of cast KV turret armour when firing a 25.2 kg shell at a muzzle velocity of 525-573 m/s at 100 meters, calculations show that firing at this velocity is unacceptable, as the pressure in the barrel reaches 3500-4000 kg/cm^2. Due to the screw breech, it is not possible to increase the pressure in the barrel. The pressure of 2350 kg/cm^2 must be maintained, and this would require a charge that provides a muzzle velocity of 476 m/s or use the first charge of the M-30 howitzer, providing a velocity of only 432 m/s. In either case, the penetration of the AP shell will be less than the 76 mm gun. The only advantage of the M-30 howitzer in a KV-9 instead of an F-34 gun is the improved HE performance.

As the 76 mm gun adequately deals with all tasks required of tank artillery, using a 122 mm howitzer in a KV tank is excessive.

The installation of a 122 mm howitzer in a KV tank is initiated by the manufacturer as a reserve in the event of a shortage of 76 mm tank guns. From this point of view, it is reasonable to complete trials, after which a finished prototype and blueprints for it will be developed, according to commission conclusions.

Additional trials of 80 shots are scheduled at the Nizhniy Tagil artillery proving grounds. I ask for you to order the KV-9 tank with a U-11 howitzer shipped to Nizhniy Tagil for these trials. Notify the Artillery Committee when the tank is shipped so that we can send a representative to the proving grounds."

Sunday, 21 September 2014

In order to increase the firepower of the tank, I think it is conceivable to install a mortar system on the turret, consisting of two pairs of specially designed mortars. These mortars can be used for creating smokescreens or other tasks. Installing these mortars will not require any special modifications, and can be done on both welded and cast turrets.

Description

The mortars are paired to provide higher density of fire.

A special clutch allows for loading without leaving the turret.

The angle of elevation is constant. Changing range is done by changing the amount of gas vented from the launcher, controlled by a valve.

The lower (and side) carrier is rigid.

A shot is performed by pressing a trigger type mechanism or another device, controlled by the gunner or commander.

Horizontal aiming is performed using the tank sights, with which the mortars are aligned.

Vertical aiming is performed by the loader using the gas valve. The mortars are positioned such that the two shells will land in a fork of the desired size. Gases are vented externally.

The mortar is simple and easy to manufacture.

The mortar fires standard mortar shells.

Individual design elements

The clutch should allow the shell to fly straight, and, at the same time, allow for loading from within the turret. Three return springs allow the clutch to return to its initial position after loading.

The gas valve can be of any design, including the screw type, shown in the sketch.

The trigger device can be done like on the 50 mm mod. 1936 mortar. The trigger will fire two barrels simultaneously. Make the trigger a lever type, with a flexible shaft, on the wall next to the gunner or commander.

Other design issues are trivial and will be resolved during the production process.

Barykov's trip to England to examine British tanks in 1934 contains much commentary on a tank built by Nicholas Straussler. I have extracted the parts dealing with this tank from the report and compiled them in a separate article.

"There is only one new and completely original design, Straussler's tank. England has no Straussler tanks. According to him, only one such tank was assembled in Hungary. The main components of the tank: engine, gearbox, reversing gear, control mechanisms, and some others are used in Straussler's armoured cars. I saw two of them in the assembly plant. The description of Straussler's tank and its engine, as well as photographs, were delivered earlier. Unlike Vickers' tanks, Straussler's tank is a complicated design that is difficult to produce.
...
As was said earlier, Straussler's tank is an exception [to the rule of simplicity] and has 8 forward and 8 reverse gears. The tank can move on wheels (although it cannot be called convertible drive, as the wheels do not turn, and the tank turns by applying brakes to one side).

The engine, 135 hp, has very high compression ratios and needs ethyl or benzole mixes, a very high quality of fuel. I composed a list of conditions for acceptance of Straussler's tank. Mainly, the conditions are as follows. The tank must be trialled for 500 km, and be guaranteed for 3000 km of operation in the Soviet Union. During these trials, the following cannot break: engine, any transmission component, suspension (including wheel rubber), fan belt, and the entire cooling system. If a part breaks, it will be replaced at the supplier's cost and the trials will be repeated. In the event of a breakdown of non-essential components, the stage of trials where the breakdown happened will be repeated. Additionally, Straussler must allow our representatives to be present during armour testing, welding, and hull QA. I considered and applied the suggestions of GVMU chief comrade Pavlunoskiy in order to create optimal conditions for experience transfer to us.

I ask you to send at least four competent engineers to test Straussler's tank. The first two will supervise the hull assembly and must be sent to England in the first half of January of 1935. "

Thursday, 18 September 2014

I have written a few articles on Soviet visits to American facilities, but what about the other way around?

"Report on a business trip to the city of Gorky with a group of American specialists from May 12th, 1943 to June 5th, 1943.

Objectives of the trip:

Perform technical exercises with the technical commanders of the 5th Tank Brigade, 229th Tank Regiment, and 45th Tank Regiment on the topic of American tanks.

Perform exercises with them Military Acceptance department and repair base #97 to familiarize them with design changes made to the M4A2 and M3.

Help repair base #97 to organize the process of repairing American tanks in new workshops.

The group was composed of American specialists:

Lieutenant Colonel Grey.

Mr. Ford.

Mr. Aikanymeaux.

Mr. Thornton.

Major Konges and Captain McIntosh arrived on June 2nd.

May 14th. The Americans familiarized themselves with work that needs to be done to organize work in the new workshops. The objective of assembling the workshops and showing American methods of using it to repair tanks was set.Lieutenant Colonel Grey, aside from overall direction of the group, occupied himself with positioning equipment and organizing work in the assembly section.Mr. Ford was tasked with positioning the equipment and organizing work in the engine and transmission repair section.Mr. Aikanymeaux was tasked with directing the assembly of the radio repair workshop.

May 15th. The Americans were allowed to visit the armour warehouse, to familiarize themselves with spare parts for American tanks that have arrived. The Americans were interested in the artillery warehouse, but I told them that I do not have any information on where that warehouse is located.Colonel Zyryanov, the commander of warehouse #37, was alerted in advance, and the warehouse was appropriately prepared.At the warehouse, Lieutenant Colonel Grey had the opportunity to witness the horrible way parts shipped to the USSR were packed. Plungers, ejector casings, and other parts that were carefully machined were poured into the crate, and were covered in a layer of rust. Electric parts were packaged with hammers and pickaxes, including lightbulbs. The flywheels were packed with cylinder valve caps. The packaging itself was messy. As a result, 50% of electric components, valve caps, and other parts were useless.Additionally, the transmission radiators for the M3 were made poorly. In places where welding was to be done, there were no welding seams, leaving gaps that oil would leak through.Lieutenant Colonel Grey asked that other crates be opened. His request was granted. The packaging was of similar quality. He asked for the bill of lading, to check where the packages came from and who was responsible for them. Then, he asked to take photographs of the damaged parts, and got our permission.

On May 16th, Grey took pictures of the parts and opened crates. I asked for the crates to be put on the ground, so the walls of the warehouse were not photographed. The film was passed on to Engineer-Major Arutyunyan for development. After developing the film, we made sure that nothing was on it aside from the parts, and returned it to the Americans.During our walk on the escarpment near the Chkalov monument, Lieutenant Colonel Grey asked if he could take a picture of the view of the Volga. After alerting the NKVD of this, he received permission.

May 17th-18th. In the new workshops, repair base #97 staff and Military Acceptance staff perform exercises on modernization of M4A2 and M3 tanks, and study new simplified and more precise methods for regulating the M4A2 engine and controls. On May 18th, a report is made to the chief of the armoured center, Lieutenant-Colonel Poruchikov, on the possibility of receiving consultation from the Americans regarding training and marching units,

May 19th-May 22nd. The technical staff of the 229th Tank Regiment participate in exercises on adjusting the engine and controls on 5 uncalibrated tanks. Technicians were present that completely mastered the adjustment process. Simultaneously, Mr. Aikanymeaux helped the regimental communications chief repair 4 radios.15 Browning 12.7 mm AA machineguns were nonfunctional in the regiment. Mr. Thornton attempted to fix them, fruitlessly, giving away his poor knowledge of armament. Several machineguns have been repaired by the repair base gunsmith, the rest were already undergoing repairs by regimental gunsmiths.Exercises were held, as a rule, from 10:00 to 15:00. After dinner on these days, work was done on repairing tanks and building new workshops.

On May 23rd, after speaking with Moscow on the telephone, Lieutenant Colonel Grey discovered that Major Olsen was leaving for American. As a result, Grey left for Moscow to give Olson appropriate directions.

On May 23rd and 24th, due to a request by Engineer-Major Muravyev, repairs of an M4A2 tank with asynchronously functioning engine regulators were enacted. The regulators were replaced with GMC 6004 and GMC 6046 regulators.

On May 26th, Lieutenant Colonel Grey returned from Moscow with a large amount of technical literature.

On May 26th and 27th, the design for a new radio workshop was approved, and assembly began. Additionally, Grey checked on the engine repair workshop design.

On May 28th, the Americans familiarized themselves with the T-34 tank. A tank and crew from the 3rd Tank Brigade were prepared. The location was distanced from the brigade location. The commander of the brigade, Colonel Nemi, his assistants, and Engineer-Major comrade Arutyunyan were present. The Americans inspected the tank inside and outside, after which each one of them drove the tank. Grey demonstrated an excellent tank driving ability, the rest drove satisfactorily. The Americans had an excellent impression of the tank and commanders. Indeed, the behaviour of the commanders was by the book.Engineer-Major Arutyunyan included a petition in his request to award a "For Excellent Driving" tanker badge to Lieutenant Colonel Grey, as he has demonstrated his excellent ability to drive a T-34 now and an M4A2 with S-series injectors back in the winter.

May 29th. Preparations for the technical meeting on the location of equipment in the engine repair workshop.In parallel with the Americans, workshop chief Sergeev composed a layout plan. Comrade Sergeev used equipment blueprints, given to him by the Americans.

May 31st and June 1st. Exercises with the technical staff of the 5th Tank Battalion on the topic of M4A2 and M3 tanks.

June 2nd. Major Kenges and Captain McIntosh arrived. Gray assembled all Americans and gave them new orders on organizing the workshops.

June 3rd. The technical meeting on the topic of new workshops was held. Comrade Sergeev presented his plan. Several major changes were made, and this project was approved as the workshop layout. At the same time, the decision to make a general assembly and disassembly line was made, and the issue of auxiliary workshops explored.The assembly and disassembly line was assigned to Major Kenges, Captain McIntosh was assigned the artillery workshop.

June 4th. Major Kenges presented his design of the assembly and disassembly line. The project review was not finished, and was postponed to the following day.

June 5th. I was ordered to Moscow by the assistant of the 5th department chief, comrade Chugunov, and left for Moscow to report on completed work and to receive new directions for the Americans.

June 8th. According to orders from TU chief, Engineer-Colonel comrade Afonin, I left for Gorky to receive orders from Lieutenant-General Lebedev regarding further presence of the Americans in Gorky, due to exceptional circumstances. The Americans have already left for Moscow according to orders given to Major Chugunov by Lebedev.

Overall issues:

Food and housing was organized as well as it was in December of 1942.

Cultural amusements: there were several operettas organized, as well as walks on the shore of the Volga.

I remained in constant communication with the NKVD on all issues.

Conclusions:

A group of Americans lead by Lieutenant Colonel Grey in Gorky resulted in great help to technical commanders of the 229th Tank Regiment and 5th Tank Brigade on the issues of organizing technically correct use and service of American tanks.

At repair base #97, the Americans demonstrated an ability to organize a correct technical repairs process that can be transferred to tanks of any type.

Major Kenges, during his short presence, proved himself to be a knowledgeable specialist. Captain McIntosh did not have enough time to fully show his abilities, but is likely very familiar with armament and electrical equipment.

Special attention should be paid to Thornton: he knows a little of everything, but is not a specialist, having only the vaguest idea about armament, even though he was sent here as an armament specialist.

Overall, technical staff at Repair Base #97 received great help with repairing tanks and using equipment.

Wednesday, 17 September 2014

Barykov's report on his presence in England jumps back and forth between his assessment of British tanks as a whole and Straussler's tank in particular. This article will deal with the general assessment, and another will deal with the specific vehicle.

"Short report in addition to the report sent by the director of the Experimental Kirov Factory, Engineer N.V. Barykov, on the trip to England

After inspecting Vickers tanks, viewing video reels, and talking to engine manufacturers and engineer Straussler, it can be said that the following vehicles are used in the English army:

4.5 ton tank with a 90 hp water cooled Meadows engine, with a maximum speed of 65 kph on a good English highway.

8 ton Vickers tank with a 90 hp Armstrong-Siddeley engine, known to us.

16 ton tank with a 180 hp Armstrong-Siddeley engine with a maximum speed of 45 kph, armed with a 37 mm gun and two machineguns.

8 ton Vickers tank with one turret and a 120-130 hp Rolls-Royce engine, with a speed around 40-45 kph.

According to Captain Lloyd, this last vehicle is experimental, although work on it has been going on for 1.5 years. Lloyd said that the manufacturer wants to change the cooling system, remove the oil cooler, change the air intake system, and in general alter the prototype for another 1.5 years.

The suspension of the Vickers/Rolls-Royce vehicle is of interest, being the Vickers 6 ton suspension, but significantly more robust. The road wheels increased in size and are completely metallic, and the number of springs has increased to 14. Due to the Rolls-Royce engine, the vehicle is supposed to be simple and reliable. It would seem that some components still need work. During the trials I observed, the rim of an idler burst, which led to the track breaking off.

I already wrote that the engine is shifted to the side, and, due to this, a hatch can be made in the rear of the turret platform for the crew to exit through during a forced stop on the battlefield.

Aside from the aforementioned vehicles, there is a tank with an air cooled 120 hp Armstrong-Siddeley engine. It is top secret and undergoing trials at the Woolwich arsenal. No characteristics of this vehicle are known. It cannot even be said if the vehicle has a convertible drive or travels on tracks only.

There is a heavy tank, a five turret Vickers, 32-35 tons, with a 350 hp engine. Judging by the engine factory, there is a very small number of these tanks.

...

Main tendencies in English tank-building:

The fight for reliability. This is achieved by maximal simplification of the design. As a rule, English vehicles run only on tracks. Inside the tanks, unlike in ours, there is a minimal amount of armament, ammunition, and various mechanisms. English tanks cannot be called universal.

Pursuit of high speeds, even at the cost of armour.

Presence of a power reserve in proportion to the weight of the vehicle. It appears that this rule only applies up to 16 tons.

The lack of many auxiliary components makes the tank roomy and comfortable for the driver and crew. I think that the question of equipping our tanks can be revisited with the objective of freeing them from unnecessary parts.

...

Having visited the car show, I noticed that many vehicles had an engine in the rear. These chassis are ready for armouring. If the engine is in the rear, it is possible to place the crew, ammunition, and armament in the front.

Out of vehicles with front engines, the following are of interest:

Citroen vehicle, completely original. Each of the four wheels has an independent suspension. This vehicle can drive over rough terrain while retaining horizontal hull positioning, which is important for firing on the move. This suspension can be used for armoured cars and tankettes. Straussler's armoured car includes all the elements of the Citroen car in its suspension. Additionally, the Citroen vehicle has a very low center of gravity, which makes it very stable. The car costs 450 Pound Sterling, and can serve as a prototype for developing a series of Citroen improvements domestically.

The other two vehicles, Singer and Austin, solve the issue of hydraulically disengaging the main clutch and synchronized gearboxes, which can automatically change the gear of a vehicle depending on terrain. These vehicles are inexpensive, costing only 250 Pound Sterling apiece. Purchasing these vehicles could aid us in the solution of the problem of creating a reliable and simple gearbox for light tanks.

The headlights on the Talbot car, with spiral light reflectors, are of interest. They can be used to drive in fog. The new type of jack is also interesting.

Experimentation

Each factory has a solid foundation for experimental work on the topics of improving existing vehicles and creating new ones. The experimental departments devote great attention to improving metalwork, improving casting, replacement of materials, etc. Much work is being done on improving the robustness of individual components. An example of this are the engine cylinders in the Armstrong-Siddeley 90 hp engine. Aside from these private design centers, there are state centers for experimental tank building, which are tasked with the creation of new secret prototypes, testing all new developments at tank factories, and representing the interests of the military directorate.

Tuesday, 16 September 2014

"To the deputy People's Commissar of Defense and Chief of the Red Army GAU, Marshall of the Soviet Union, comrade Kulik

On the issue of testing German half-track tractors.

Along with the 305 mm Czech howitzer and 211 mm German howitzer, we received two halftracks from the GABTU proving grounds:

12-ton Daimler-Benz tractor

18-ton FAMO tractor

Since the Daimler-Benz tractor was received in nonfunctional condition, and the ANIOP garage could not repair it, only the 18-ton FAMO tractor underwent trials.

Trials took place between January 21st and February 5th, 1941, under the supervision of a special commission.

Mobility trials showed the following:

The average technical speed of the tractor is 20 kph, which is the same as the speeds of domestic Comintern and Voroshilovets tractors.On good, flat, wide roads, when there is no oncoming traffic, the tractor can reach speeds of 50 kph with a trailer.

Its robustness, reliability, and design show it to be a modern quality vehicle, capable of 2500 km marches without significant breakdowns. The engine is 50% weaker than the Voroshilovets engine, but the speed data is identical to the Voroshilovets tractor.

The following components are of interest: gearbox, demultiplexer and double differential in one assembly, suspension, tracks with needle bearings, clutch, compressor, odometer.

The tractor has poor traction with the ground. When towing a 3000 kg weight, its tracks begin to slip.

The tractor does not turn in a satisfactory manner. A 180 degree turn is only possible in wide open spaces and crossroads of wide roads. When the tractor is towing a cannon, a 90 degree turn is only possible after detaching the cannon. Maneuvering while towing a cannon is impossible.

Due to high ground pressure of the front wheels (4-4.5 kg/cm^2) and tracks (0.7-2.33 kg/cm^2), poor maneuverability, and poor traction, off-road mobility of the tractor is limited.

The tractor uses a gasoline engine. Its fuel is high quality aircraft gasoline, which makes use expensive.

Since 8-ton and 12-ton tractors are identical to the 18-ton tractor, with the exception of the Daimler-Benz which uses a diesel engine, the same conclusions can be made about them.

Since the German half-tracked tractors have poor maneuverability, poor ground traction, and limited off-road capability, it is not sensible to make similar tractors for Red Army artillery units."

Monday, 15 September 2014

By the fall of 1916, the British and French offensive against the Germans at the river Somme in North France petered out, having set into a positional meat grinder. Both sides tried to tear through a maze of trenches wrapped in barbed wire, fruitlessly. In the first day of the offensive, the British lost 20,000 men dead and 40,000 wounded from machinegun and artillery fire, while the Germans lost 6,000 men. It seemed that there was no way to change the situation.

Steel Ace
As a last ditch effort to achieve success in this long and bloody struggle, the British General Douglas Haig placed his faith in new combat vehicles. To preserve secrecy, they were called "tanks".

The British began making tanks in 1915. By the summer of 1916, the amount of vehicles approached 50. The rhomboid tracked monsters were indexed MkI and MkII, and were made in two modifications. Tanks with only machineguns were called "female", and were meant to fight enemy soldiers. "Male" tanks were equipped with a machinegun and two 57 mm guns.

After transport to the mainland, the tanks were moved towards the front line in utmost secrecy. Nighttime marches in unscouted terrain proved difficult for the MkI; 17 of them were bogged down in mud or suffered mechanical failure. 32 vehicles reached their starting positions.

With their new vehicles, the British expected to knock the Germans out of Guedecourt and Fleur. In platoons of 2-3, the tanks were to penetrate enemy lines in its most powerful sections, covering advancing infantry. The first to enter the battle was Captain Mortimer's "male". It was 5:15 on September 15th, 1916. The tank approached German lines between Ginchy and Delville Wood. It destroyed a machinegun nest that impeded British light infantry, but was then knocked out by an artillery shell to the suspension.

At 5:30, other tanks entered combat. Their crews were suffocating due to fumes, the sound of cannon fire and hammering of bullets against the armour deafened them. It was very cramped inside, next to the spare oil tank, two small gas tanks, three water tanks, spare machinegun barrels, a spare machinegun, a cage with postal pigeons, a signal flag, and a set of signal lamps. Of course, there also had to be room for two days worth of food and the crew's personal equipment.

Germans in shock
In the first years of WWI, psychosis caused by unending artillery explosions (shell-shock) was a common affliction for a soldier. The Germans were even more shocked by the appearance of tanks. When a German screamed "The Devil is coming!" in the first trenches, his words spread like wildfire. Through the tanks' observation slits, one could see many figures in feldgrau uniforms fleeing from their positions. The few brave men that attempted to open fire at these steel monsters were unsuccessful.

The tanks advanced. Far from perfect, they thundered as they fell into German trenches or got stuck in shell craters. Crews had to climb out to attempt to repair the tank. However, those MkIs that were spared this fate performed well.

For instance, the male D17 "Dinnaken" commanded by Lieutenant Hastie was the first to enter the village of Fleurs, slowly following running and hiding Germans. An airplane reconnaissance mission reported "The tank is moving through the main street of Fleur, English soldiers are following it in good spirits".

Other vehicles were of great help to infantry, making holes in barbed wire and crushing machinegun nests. One MkI stopped above a German trench, cleared it with machinegun fire, and proceeded to move along the trench. With its help, approximately 300 enemy soldiers were captured. 10 tanks were knocked out during the attack for various reasons, 7 more received superficial damage.

Local success with serious consequences
How effective was this use of tanks? A certain tactical success, but one that failed to turn the tide of battle.

On one hand, the British moved several kilometers forward over a front of 10 kilometers in only five hours, with minimal losses. Positions were taken that were attacked before, without success. Douglas Haig, who viewed tanks sceptically, ordered an additional thousand vehicles.

On the other hand, the British lost the element of surprise, as the effect from a sudden appearance of these stunning tanks could have been much greater. As it was, the news of their use travelled around the front lines, then around the world. Spies and engineers in nearly every nation participating in WWI got to work.

The Russian Empire did not have time to make its own land battleships, but carefully watched their evolution. Documents of the General Staff contain such reports as this one, for December of 1916: "In Germany, Krupp, Ehrhart, and Hans-Lloyd factories in Bremen are at work making 120 "tanks", for now...only two types. It is expected that they will be used on all fronts, for offence, not defense. The best weapon against these "tanks" is a 3.7 centimeter trench gun."

The word "tank" is used awkwardly. However, events of September 15th, 1916, made "tank" an international word, and assigned to it a military meaning. From that moment on, war took a more modern turn.

Article author: Yuri Bakhurin. Yuri Bakhurin is a military historian, an author of many publications in regional and central scientific press: "Questions of History" magazine, "Military-Historical Magazine", "Military-Historical Archive", "Motherland", "Anthology of War", the "Reitar" almanac, and many more. He is also the author of the "Panzerjager Tiger (P) Ferdinand: Use in Combat" book.

Sources:

F. Mitchell, Tank Warfare. The Story of the Tanks in the Great War, Moscow, 1935

RGVIA 802-4-1477, Materials on fighting tanks in the event of their use by foreign powers

Sunday, 14 September 2014

"It's complicated" is a good way to describe the American relationship with heavy tanks in the first half of the 20th century. The Anglo-American "Liberty" tank became the top of the "rhombus" concept, but was obsolete by early stages of production. Experimental T1 and M6 tanks ended up with a fine collection of technical problems and never left the prototype stage. The Pershing appeared towards the end of WWII, but was named a heavy tank only to calm down tankers: don't worry, we have a real heavy tank, no worse than a King Tiger. Little needs to be said about the T28/T95, the Americans did not even decide whether to call it a heavy tank or SPG.

29+5 or 30+4
In June of 1944, the Allies landed in Europe. Many reports from the front lines of German heavy tanks became a weighty argument for accelerating the heavy tank program. A document describing two new heavy tanks was signed on September 14th, 1944. Engineers were to create the T29, with a 105 mm gun, and the T30, with a 155 mm gun.

In April of 1945, the military ordered that one of the T29 prototypes should be equipped with a 120 mm T53 gun. This vehicle was initially indexed T34. However, due to the end of WWII, work on the T29 slowed down, and this T34 prototype was never built.

The issue of increasing the firepower of tanks was still unsolved. The T53 gun, based on the 120 mm AA gun, could fire a shell at 1100 m/s, which was a very good result in those days. A HVAP shell with a tungsten core could reach speeds of 1300 m/s. In the middle of May of 1945, it was decided that this gun would be put into two prototype T30 tanks. The T34 index migrated to these vehicles.

Aside from the gun, the T34 had a different turret than the T30. In order to balance the long gun, a counterweight was installed on the rear. Otherwise, the vehicles were identical. In 1946, an experimental T34 was ready.

Backfire
During trials at Aberdeen and Fort Knox, the military was faced with two serious issues. One was that the ventilation could not handle the amount of gases that formed during firing. After several shots, the concentration of gases inside the turret reached dangerous levels.

The second problem was that several tankers ended up in the hospital with burns. After firing, the barrel still held some amount of hot gases. As soon as the breech opened to extract the casing, they were sucked back into the turret, mixed with air, and ignited.

The problem was resolved with a fume extractor, a special device to extract excess gases from the barrel. It was installed on the cannon, near the muzzle. This device was already successfully used on several other tanks.

The T34 was not mass produced. Only two experimental vehicles were built. In the 1940s, the Ordnance Department re-evaluated its heavy tank plans, in part due to the appearance of the IS-3, which was lighter than its American equivalents, but had superior protection and comparable firepower.

As a part of an overall downsizing of the military budget, the T29, T30, and T34 programs were first reduced in scope, then cancelled completely. Most finished prototypes were scrapped. One T34 escaped this fate, and is currently present in the Patton museum at Fort Knox.

Article author: Vladimir Pinayev
Sources:

P. Chamberlain, K. Ellis, British and American Tanks of WWII, Moscow, Astrel, 2003

R. Hunnicut, Firepower: A History of the American Heavy Tank, Presidio, 1987

Saturday, 13 September 2014

"Extract from the act on the comparative trials on T-80 and T-70 tanks, conducted as a result of NKSM and GABTU KA order #6135, issued on December 4th , 1942

Summary:

The combat qualities of the T-80 tank, such as

Armour

Practical rate of fire

Accuracy

Ability to fire at airborne targets

Visibility

Crew comfortsurpass those of the T-70 tank, and meet the requirements for a light tank.

The increased crew of 3 drastically increases the T-80's combat performance compared to the T-70B, and improves the control of tanks in battle. It is easier and faster to service the tank with three men.

The installation of two turbocharged GAZ-80 engines with a total power of 170 hp results in an effective 15 hp/ton, which provides the T-80 with better or equal performance compared to the T-70B.

The 45 mm gun with an additional return mechanism designed by Gorkiy factory performed flawlessly during trials (875 shots).

Drawbacks of the T-80 include:

The turret and turret platform ceiling must be removed to replace the engines, which will complicate field repairs.

Turbocharging the GAZ-80 engine resulted in large compression and filling ratios, which means that the cylinders, cylinder heads, valves, and cylinder liners are incompatible with the stock 6-cylinder engine.

Conclusions:

The commission considers it possible to recommend the T-80 for adoption by the Red Army to replace the T-70, pending correction of all defects outlined in this act and factory trials."

Friday, 12 September 2014

I've posted some critiques of American M3 tanks, both light and medium, before, but these are a bit more special. Not only are they a lot more complete, but they are based on the very first use of these tanks in combat on the Eastern Front.

"Based on combat experience of using M3 medium and M3 light tanks in the 153rd Tank Brigade, and also experience from June 24th to August 31st, the following can be said. These tanks can be used to break through a defensive line, even in the presence of dense enemy anti-tank fire. The presence of powerful armament and robust armour allows for successful combat with enemy tanks and infantry. During pre-battle use and combat use in the brigade, the light and medium tanks showed the following strengths and weaknesses:

Armour. The front and turret armour stands up well against hits from HEAT shells. All hits to the front of the tank, especially the medium tanks, fail to penetrate the entire thickness of the armour. As a rule, the shell melts the first layer, and then gets stuck. As such, it fails to penetrate into the tank. The side armour, due to its insufficient thickness, is easily penetrated by AT guns, and the top armour can be penetrated by mortars. A drawback of the turret design is that if it is hit by a mortar shell, it jams. There were also instances of the gun mantlets of 75 and 37 mm guns jamming.

The cannons and machineguns are sufficiently powerful, but the Browning machinegun has several design defects. These defects result in casings tearing during automatic fire, which jams the machinegun. The cannons work flawlessly. Crew workspaces in the tank are mostly comfortable. Shells for the 75 mm gun are placed well. Shells for the 37 mm gun are placed inconveniently, as some of them are placed in the main fighting compartment. When all 37 mm shells in the turret are used up, it is impossible to get more shells when the tank is moving. This can only be achieved with help from the 75 mm gun loader, which reduces the rate of fire and makes his job very difficult.

Tank components. Having used the tanks for two months, during long 110-160 km marches on difficult terrain, it can be seen that the engine group works flawlessly. "Continental" motors on light tanks had cases of articulated connecting rods tearing off, which indicates a design flaw. There have been cases of hoses that connect the air intake and carburettor being damaged. Transmission components mostly behave well, except in two cases of the main friction clutch and 3rd adn 4th gears getting jammed on light tanks. There were two cases of road wheels getting jammed in their bogies (in light tanks). The double differential makes braking reliable. All components are placed conveniently from a maintenance perspective. However, the engine is placed inconveniently for adjusting valves. When performing this operation, it is necessary to remove the upper and lower rear armour plates. Over two months, the controls worked flawlessly, and did not require adjustment. The cooling system works well in the summer, and guarantees proper operation of the engine (no overheating was detected).

The use of high quality gasoline results in immediate ignition when hit by incendiary shells.

There are not enough observation devices, and communication inside the tank is poor. The radio works flawlessly.

Observation devices and sights break when the armour is hit by shells or bullets, even when this happens a significant distance away from the device.